fix bug when switching to a study chapter without analysis
fix bug when switching to a study chapter without analysis

luanlv/lila,arex1337/lila,arex1337/lila,luanlv/lila,arex1337/lila,arex1337/lila,arex1337/lila,arex1337/lila,luanlv/lila,luanlv/lila,luanlv/lila,arex1337/lila,luanlv/lila,luanlv/lila